Amid a crackdown on collection practices, industry veteran Encore Capital should gain share. It might even get bought out.

The good news is that wages for collection agents have risen 4% over the past year, more than double the pace for typical workers, according to Labor Department data. That suggests that the agencies are prospering, because their worker pay is closely linked to success in collecting on delinquent bills.

The bad news is that regulators are finally cracking down on abusive...